Photosynthesis, CO2 and temperature – an approach to analyse the constraints to acclimation of trees to increasing CO2 concentration
Juurola E. (2005). Photosynthesis, CO2 and temperature – an approach to analyse the constraints to acclimation of trees to increasing CO2 concentration. https://doi.org/10.14214/df.4
Abstract
The aim of this thesis was to analyse the effects of temperature and increasing CO2 concentration on the processes involved in photosynthesis and on acclimation of the photosynthetic machinery within the constraints set by three-dimensional (3D) leaf structure. These processes include both the transport of CO2 into and within a leaf and the photosynthetic CO2 sink in the chloroplasts. A detailed 3D model of silver birch leaf photosynthesis was constructed to study the transport of gases into and inside a leaf as well as the light attenuation inside a leaf. To understand the role of temperature in apparent CO2 assimilation, the temperature dependencies of essential biochemical reactions in photosynthesis were experimentally determined for silver birch and for boreal conditions utilising a conventional model of photosynthesis. The role of temperature dependent physical phenomena in the apparent CO2 assimilation was analysed in detail using the 3D model. Based on these results, new chloroplast related temperature dependencies describing the biochemical processes were determined that take into account the specific effects exerted by leaf structure and CO2 diffusion. Finally, the patterns of acclimation of photosynthesis to increasing CO2 concentration were experimentally studied in silver birch and Scots pine. The developed model is a powerful tool for studying photosynthesis in a 3D leaf. The results showed clearly that the physical phenomena together with leaf structure play an important role in leaf CO2 assimilation and that these have to be included in the analysis of photosynthesis in a changing environment. It was also concluded that besides other factors, leaf structure may significantly influence the acclimation patterns of different tree species when atmospheric CO2 concentration is increasing. Due to the structural differences, in contrast to silver birch, Scots pine may be able to take full advantage of increased CO2, at least temporarily.
Keywords
climatic change;
CO<sub>2</sub> diffusion;
leaf structure;
modelling;
temperature dependence
Published 2 September 2005
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Available at https://doi.org/10.14214/df.4 | Download PDF
Original articles
Aalto, T. & Juurola, E. 2001. Parametrization of a biochemical CO2 exchange model for birch (Betula pendula Roth.). Boreal Environment Research 6: 53–64.
http://www.borenv.net/BER/pdfs/ber6-053s.pdf
Aalto, T. & Juurola, E. 2002. A three dimensional model of CO2 transport in airspaces and mesophyll cells of a silver birch leaf. Plant, Cell and Environment 25: 1399–1409.
https://doi.org/10.1046/j.0016-8025.2002.00906.x
Juurola, E., Aalto, T., Thum, T., Vesala, T. & Hari, P. 2005. Temperature dependence of leaf-level CO2 fixation: revising biochemical coefficients through analysis of leaf three-dimensional structure. New Phytologist 166: 205–215.
https://doi.org/10.1111/j.1469-8137.2004.01317.x
Juurola, E. 2003. Biochemical acclimation patterns of Betula pendula Roth. and Pinus sylvestris seedlings to elevated carbon dioxide concentrations. Tree Physiology 23: 85–95.
http://heronpublishing.com/tree/summaries/volume23/a23-85.html